PBX1 and cancer: Quantitative RT–PCR (qRT-PCR) further showed that Bcat1 (related to BCAA metabolism) or Hoxa9, Ccnt1, Pbx1, Rora and Pbx3 (related to transcriptional misregulation in cancer) were significantly reduced in P2x1-null LICs (Fig. 3C and Table S2), suggesting that these genes may act as downstream targets of P2X1.